In the packaging of integrated circuits, a plurality of dies may be bonded on an interposer wafer, which comprises a plurality of interposers therein. After the bonding of the dies, an underfill may be dispensed into the gaps between the dies and the interposer wafer. A curing process may then be performed to cure the underfill.
It was found that underfill may shrink after being cured. As a result, the cured underfill applies a force on the dies and the interposer wafer, and hence may cause the interposer wafer to have a warpage. The warpage of the interposer wafer further results in the process difficulty in the subsequent processes. For example, in a subsequent process (e.g. molding, grinding, thin film, or the like), the interposer wafer needs to be secured on a chuck table through vacuum. With the interposer wafer having the warpage, however, the interposer wafer may not be able to be secured on the chuck table.